At least 12 people have been killed and scores injured on Thursday in twin bombings that authorities believe may have been a terrorist attack in the southern Indian city of Hyderabad. There has been no official confirmation as to the nature of the blasts, but government officials have said they were carried out by a “well trained” group and were coordinated.

Local media are reporting that the blasts come two days after government security agencies sent an advisory to states to tighten security in light of potential threats from militant groups operating in the region related to the recent executions of convicted terrorists Ajmal Kasab and Mohammed Afzal Guru.

In tweets sent out after the attacks on Thursday evening, Indian Prime Minister Manmohan Singh appealed to the public to remain calm. “This is a dastardly attack, the guilty will not go unpunished,” he tweeted. The attack was the first major bombing in India since a blast outside a court in New Delhi in 2011 that killed 11 people.

KRISHNENDU HALDER / REUTERS

Police examine the site of an explosion at Dilsukh Nagar in the southern Indian city of Hyderabad on Feb. 21, 2013

India has been on alert since Guru, who was Kashmiri, was executed earlier this month in New Delhi’s Tihar Jail. Guru was convicted of involvement in the 2001 attacks on Parliament in which 14 people were killed, but many in Kashmir in particular believe he did not receive a fair trial and were upset by the handling of his execution.

Forensics teams have reportedly been deployed to the bomb sites along with officials from the National Investigative Agency and Intelligence Bureau. The bombs, which authorities say were attached to two bicycles, were detonated around 7 p.m. outside a movie theater and bus station in a busy area of the city of some 10 million people, according to police.

Singh, in addition to condemning the attacks, announced the government would give 200,000 rupees ($3,700) to relatives of the deceased and 50,000 rupees ($900) to those injured in the attacks. Further compensation has also been offered by the chief minister of the state of Andhra Pradesh, where Hyderabad in located.

Almsgiving after terrorist attacks, though, is an unfortunate tactic all too frequently deployed by the government. Long-standing questions about the capability of India’s security and intelligence infrastructure — which reached their highest pitch following the shocking, deadly 2008 assault on one of Mumbai’s ritziest neighborhood — are once more being raised. And speculation swirls: some analysts point the finger at the Indian mujahedin, an Islamist extremist group. In 2007, Hyderabad suffered twin bombings that claimed at least 42 lives; blame then fell on Harkat-ul-Jihad Islam, another extremist group then anchored in Bangladesh.

But no clear leads have emerged, and both politicians and TV commentators urged caution against “rumor mongering” in the breathless hours that followed the attack. Hyderabad, a historic city that’s now one of India’s leading tech centers, is also at the heart of the Telangana movement, which seeks to carve a new state out of Andhra Pradesh. Tensions surrounding the bid have flared up in recent years.